It is estimated that 73% of Americans between the ages of 65 to 74 get cataracts. A cataract is a clouding of the eye's lens that impairs a person's vision and, if left untreated, causes blindness. As a result, each year approximately 1.4 million people in the United States alone undergo cataract surgery, whereby the clouded natural crystalline lens is removed and replaced with an intraocular lens (IOL) implant.
Surgeons implant IOLs not only as a replacement for the natural crystalline lens but also to alter the optical properties of (provide vision correction to) an eye in which the natural lens remains. IOLs often include an optically clear disk-like optic of about 6 mm in diameter, and preferably at least one flexible fixation member or haptic which extends radially outward from the optic and becomes affixed in the eye to secure the lens in position.
The optics may be constructed of rigid biocompatible materials such as polymethyl methacrylate (PMMA) or deformable materials such as silicone polymeric materials, acrylic polymeric materials, hydrogel polymeric materials, and the like. The deformable materials allow the IOL to be rolled or folded for insertion through an injector or insertion cartridge and an incision into the eye. Once within the chamber of the eye, the IOL is expulsed from the injector and returns to its original shape.
Injectors or inserters for delivering IOLs into the eye typically employ a handpiece and a removable cartridge that receives the IOL and has a hollow insertion tube or cannula through which the folded IOL is passed using a push rod. Some inserters do without the cartridge. The inserter may be wholly or partly reusable, in which case the inserter or handpiece is usually made of some type of metal alloy that can be sterilized. Alternatively, disposable inserters made of less expensive materials, such as plastics, remain in a sterile package until ready for use. In all cases, the IOL is stored separately and transferred to a load chamber in the inserter or cartridge just prior to delivery. One particularly useful arrangement wherein the cartridge folds over an IOL is disclosed in U.S. Pat. No. 4,681,102 to Bartell. A cartridge opens to receive an IOL in a load chamber, and then folds closed and fits into an injector. A syringe-like plunger in the injector pushes the IOL from the load chamber through a tapered tube into the eye. The IOL unfolds as it emerges from the tip of the tapered tube. Another such insertion system is disclosed in Makker et al., U.S. Pat. No. 5,942,277.
One problem encountered with existing inserters is difficulty in loading the IOL into the inserter or cartridge. The IOL is typically manually moved from a sterile environment to an inserter or associated cartridge using forceps or tweezers. Manual transfer of the IOL presents difficulties in maintaining both sterility of the IOL and the correct orientation of the IOL, especially the haptics, within the cartridge or inserter. A wide variety of performance and outcomes results even with highly skilled personnel, and those having less training are more likely to perform poorly. Improper orientation of the IOL can result in inadequate surgeon control and even damage to the IOL during delivery into the eye.
These problems may be mitigated by preloading the IOL at the manufacturer into a cartridge or container that is designed to be included directly in the inserter. The cartridge or container may be attached to the inserter either at the manufacturer or by the user just prior to surgery. The IOL is stored directly in the inserter in an unstressed state in a sterile package in order to prevent deformation of the optic element. A transfer process is not generally necessary for loading the IOL into the inserter. One example of storing an IOL in an inserter component is seen in U.S. Pat. No. 7,156,854, filed May 28, 2003. In the '854 patent, a nozzle portion 12 along with a removable stop 26 retains the IOL therein during storage and has internal ramps that assist in folding the IOL optic during an implant procedure. Also, U.S. Patent Publication No. 2008-0058830, filed Jul. 17, 2007, discloses a number of configurations for pre-loading IOLs for transfer to an insertion apparatus, and is expressly incorporated herein.
Despite some advances in this area, there remains a need for devices, systems, and methods that facilitate the placement of IOLs into an inserter or cartridge to reduce the problems associated with manual IOL manipulation.